1. Field of the Invention
The present invention relates to a plasma display apparatus, and more particularly, to such a plasma display apparatus having an electrode pad.
2. Background of the Related Art
FIG. 1 is a dismantled perspective view of a common plasma display apparatus.
As shown in FIG. 1, the common plasma display apparatus includes an upper structure and a lower structure. The lower structure has a lower substrate 9 and an address electrode 2. The upper structure includes an upper substrate 1, a scan electrode 3, a sustain electrode 4, a dielectric layer 5 and a protection layer 6. The lower structure further includes barrier ribs 7 that support between-the upper substrate 1 and the lower substrate 2, and a phosphor layer 8 coated on a surface of he barrier ribs 7. An inert gas is injected into a space between the upper structure and the lower structure, forming a discharge region.
In the common plasma display apparatus constructed above, sufficient charges are generated in the entire discharge cells on a plasma display panel by applying a ramp-up pulse to the scan electrode 3 in a set-up period. Thereafter, in the common plasma display apparatus, a ramp-down pulse is applied to the scan electrode 3 in a set-down period, erasing a predetermined amount of charges. The charge distribution of the entire discharge cells becomes uniform.
In the common plasma display apparatus, an address pulse and a scan pulse are applied to the address electrodes 2 and the scan electrode 3, respectively, in an address period, thus selecting a cell to be turned on.
Thereafter, in the common plasma display apparatus, a sustain pulse is alternately applied to the scan electrode 3 and the sustain electrode 4 in a sustain period, so that a sustain discharge is generated in the cell selected in the address period.
For this operation, a driver IC of the common plasma display apparatus applies a driving pulse to  the address electrodes 2, the scan electrode 3 and the sustain electrode 4 of the plasma display panel through an electrode pad.
FIG. 2 is a plan view showing an electrode pad of a conventional plasma display apparatus.
As shown in FIG. 2, the electrode pad of the conventional plasma display apparatus includes a glass substrate 111, an electrode part 110 formed on the glass substrate 111, a white-back layer 112 disposed on one side of the electrode part 110, an Anisotropic Conductive Film (ACF) 113 disposed on the other end of the electrode part 110, and a connector 114 having a connector electrode 115 corresponding to the electrode part 110. At this time, the connector 114 applies a driving pulse, which is received from an electrode driving unit (not shown), to the electrode part.
In this case, the connector 114 is a COF (Chip On Film), a TCP (Tape Carrier Package) or a FPC (Flexible Printed Circuits), which becomes the cause for raising the manufacturing cost of the plasma display apparatus. Accordingly, in order to prevent the manufacturing cost from increasing due to the connector 114, the electrode pitch becomes minute. As the electrode pitch becomes minute, electrodes frequently become short due to a migration phenomenon. The migration phenomenon is a phenomenon that an ionized electrode material moves around.
More particularly, in the case of the conventional electrode pad, shortage is frequently generated at the interface between the ACF 113 for connecting the connector 114 and the electrode part 110 due to migration. Furthermore, since the width of the existing electrode part 110 is constant, there is a high possibility that the shortage due to migration can occur in the electrode part 110 exposed between the white-back layer 112 and the ACF 113 as the electrode pitch becomes minute. In addition, as the electrode pitch becomes minute, an align tolerance of the electrode part 110 and the connector electrode 115 is reduced. Thus, the defect probability is further increased. Further, as the pitch of the electrode part 110 becomes minute, the contact property between the electrode part 110 and the connector electrode 115 is lowered.